Unit 7 - Astronomy

Question 1

What was Ptolemy’s idea?

Answer 1

That Earth was in the centre and everything orbited it (geocentric model)

Question 2

What was Copernicus’ idea?

Answer 2

That the sun was at the centre of the solar system (heliocentric model)

Question 3

What are comets mostly made from

Answer 3

Ice

Question 4

What does our current solar system model show?

Answer 4

8 planets, 5 dwarf planets, thousands of comets and millions of asteroids

Question 5

What did the invention of photography allow astronomers

Answer 5

To make more detailed observations and measurements

Question 6

What are computers used for by astronomers

Answer 6

To analyse the information from telescopes

Question 7

Why do telescopes in orbit give clearer images?

Answer 7

Clouds and dust in the air do not interfere with the image

Question 8

Why must telescopes deleting certain electromagnetic waves be places in orbit

Answer 8

The atmosphere absorbs some of the radiation they are designed to detect

Question 9

What is weight

Answer 9

The force of gravity acting on you

Question 10

What is the word equation for weight

Answer 10

Weight = mass x gfs

Question 11

What makes surface gravity greater

Answer 11

A larger mass but smaller radius (denser)

Question 12

What are artificial satellites used for

Answer 12

Communications and to observe the earth

Question 13

Give 3 uses of satellites

Answer 13

Weather
Broadcasting
Photographs

Question 14

What are the 3 types of orbits satellites can be put into

Answer 14

Geostationary (over the same point
Polar orbit (over the Poles)
Low earth

Question 15

Why does an orbiting body have a constantly changing velocity

Answer 15

The direction is changing

Question 16

Is the gravitational force Ona satellite in low orbit strong or weak

Answer 16

Strong

Question 17

What will happen to the earth when our sun becomes a red giant?

Answer 17

It will get swallowed up

Question 18

What is a nebula?

Answer 18

A cloud of dust and gases (mainly hydrogen)

Question 19

How is a protostar formed from a nebula?

Answer 19

The material is pulled together by its own gravity, the hydrogen becomes hotter and starts to glow, as more mass is pulled, the gravity gets stronger and it gets hotter.

Question 20

What happens during the main sequence of a star

Answer 20

The high pressures force the hydrogen nuclei to fuse spit form helium. Fusion reactions release a lot of energy.

Question 21

What form of energy is released from fusion?

Answer 21

Electromagnetic radiation

Question 22

What stops the start in main sequence from collapsing in on itself

Answer 22

The pressure from the hot gases balance the compression of gravity

Question 23

How does a start become a red giant?

Answer 23

When most of the hydrogen has fused into helium, the core is not hot enough to withstand the gravity and collapses, th per outer layer expands to form the red giant

Question 24

What stage is our current star in?

Answer 24

Main sequence

Question 25

How long does a star remain a red giant

Answer 25

1 billion years

Question 26

How is a white dwarf formed?

Answer 26

Fusion continues forming heavier elements, the star throws of a shell of gas and the rest of the star is pulled together by gravity and collapses to form a white dwarf.

Question 27

How does a white dwarf become a black dwarf

Answer 27

No fusion happens so the star begins to cool.

Question 28

What is the life cycle of stars like ours (6)

Answer 28

Nebula, protostar, main sequence, red giant, shell of gas, white dwarf

Question 29

How is a red supergiant formed

Answer 29

If there is more mass, fusion of hydrogen happens much quicker

Question 30

How does a supernova occur?

Answer 30

At the end of a red supergiant, it rapidly starts to co,,also and then explodes

Question 31

How is a black hole formed

Answer 31

If the mass of the star is 4 times our star, gravity pulled the remains together, light cannot escape from the pull of gravity

Question 32

How is a neutron start formed

Answer 32

If the star isn’t massive enough, gravity pulls it together to form a small, very dense star

Question 33

What is the life cycle of a massive star? (6)

Answer 33

Nebula, protostar, main sequence, red supergiant, supernova, blackhole/ neutron star.

Question 34

What is the Doppler effect

Answer 34

When the pitch of sounds change due to moving or becoming closer to you

Question 35

How does the Doppler effect occur?

Answer 35

The sound waves behind the source become ‘stretched’ making the wavelength longer and the frequency lower so the pitch is lower. It is opposite if you are in front of the sound source

Question 36

What must be happening for the Doppler effect to take place

Answer 36

If the observer is stationary

Question 37

What is red-shift

Answer 37

When the patterns of the dark lines on a visible spectrum have been shifted to the red end of the spectrum due to the object moving away

Question 38

When does red - shift occur

Answer 38

When an object is travelling further away from the observer

Question 39

When does blue - shift occur?

Answer 39

When the object is moving closer to the observer

Question 40

What does red-shift show about the universe

Answer 40

That it is expanding

Question 41

Describe the speed of a large red-shift

Answer 41

Faster

Question 42

What does the Big Band theory explain about the origin of the universe?

Answer 42

All matter started as a tiny point of concentrated energy, the universe expanded from this point and is still expanding, the gravity clumped matter to form stars

Question 43

How is matter dispersed according to the Big Bang theory as it expands

Answer 43

Spreading away as it expands

Question 44

What does the Steady State theory say

Answer 44

The universe has always existed, it is expanding

Question 45

What is the main difference between the Steady State theory and the Big Bang theory

Answer 45

The BBt says matter is not created, the SSt theory says matter is created

Question 46

Why is the energy released form the Big Band theory only detected as microwave radiation

Answer 46

The universe is expanding so the wavelengths are increasing

Question 47

What is cosmic microwave background radiation?

Answer 47

The radiation that is detected from the universe

Question 48

How was cosmic microwave background radiation discovered?

Answer 48

2 radio astronomers detected the microwave signals, thought it was a fault in their equipment but realised that they were real.

Question 49

What evidence supports both the SSt and the BBt?

Answer 49

The universe is expanding due to red-shift

Question 50

Why is the Big Bang theory preferred over the Steady State theory?

Answer 50

It can support the evidence of the CMB radiation